This invention relates to tablet dispensers, and in particular to a pesticide tablet dispenser for fumigating agricultural commodities.
One method for fumigating goods such as raw agricultural commodities, grain, animal feed, and the like, comprises the process of evenly dispensing fumigant tablets into the commodity as it is being loaded into the storage container or transport vehicle. The fumigant tablets are typically made from a pesticide material, such as aluminum phosphide, which reacts with humidity in the atmosphere and emits a toxic gas, in the noted example phosphine, which permeates the commodity and kills the insects therein. The fumigant gases are quite toxic, and therefore hazardous to humans, and the tablets begin to gas as soon as they are exposed to the atmosphere.
Although the tablets may be metered into the commodity manually by workers stationed adjacent to the opening of the grain receptacle, the workers are thereby exposed to the toxic gases for a period of time which extends throughout the grain loading process. Inhalation of the fumigant gases even at such remote working stations can present a hazard to the workers' health. Further, because the workers must be positioned in the proximity of the open loading area of the receptacle, they are subject to a severe safety hazard comprising the exposure to lethal concentrations of fumigant gases should they accidently fall into the receptacle during fumigation, or otherwise unwittingly enter the fumigation area.
Machines for dispensing the fumigant tablets must be reliable and evenly distribute the tablets throughout the commodity, and further must operate without clogging. Should a fumigant tablet dispenser clog or jam during fumigation, since the tablets continue to gas after exposure to the atmosphere, immediate repair of the machine would be quite dangerous. Further, as the pesticide tablets absorb humidity from the air, the tablets become somewhat softer, and they are therefore more susceptible to breakage, which in turn causes dispenser jamming.